Backblaze B2 S3 API Authentication Error
Check endpoint, region, and API-key permissions.
Before you begin
Check whether you are using Backblaze Computer Backup or Backblaze B2 Cloud Storage. The two products have different setup, billing, and recovery procedures. Confirm your operating system, software version, and the exact error before changing settings.
Steps to follow
- Verify the region-specific S3 endpoint.
- Confirm the access key ID and secret are from the intended B2 account.
- Review bucket-scoped permissions and List Buckets requirements.
- Test with a restricted non-production operation.
How to confirm the fix
Repeat the affected task using a safe test. For Computer Backup, check that new files are being backed up and that an appropriate restore point is available. For B2, test a limited upload or download using the intended scoped credentials. A successful status message is not a substitute for a tested restore.
If the issue continues
Record the exact error, time, product, client version, and relevant non-sensitive logs. Consult the official Backblaze Help Center for current instructions. Do not remove the only backup copy, weaken access controls, or disable retention rules just to dismiss a warning.